Old Earth Ministries Online Earth History Curriculum

This curriculum is presented free of charge for use by homeschooling families.

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Chapter 14 - The
Quaternary Period

Lesson 68: The Pleistocene Epoch

The
Pleistocene
is the
epoch from 2.588 million to 12,000 years
BP covering the world's recent period of repeated
glaciations. The name pleistocene is derived from the Greek
πλεῖστος (pleistos "most") and
καινός (kainos "new").

The Pleistocene Epoch follows the
Pliocene
Epoch and is followed by the
HoloceneEpoch. The Pleistocene is the first epoch of the
QuaternaryPeriod.
The end of the Pleistocene corresponds with the retreat of the
last continental glacier. It also corresponds with the end of the
Paleolithic age used in
archaeology.

In the ICS timescale, the Pleistocene is divided into four
stages or
ages, the
Gelasian,
Calabrian,
Ionian and
Tarantian. All of these stages were defined in southern Europe. In
addition to this international subdivision, various regional subdivisions
are often used.

The Pleistocene has been dated from 2.588 million (±5,000 years) to
12,000 years

Extent of ice coverage in the Northern Hemisphere during the
Pleistocene.

before present (BP).
It covers most of the latest period of repeated glaciation, up to and including the
Younger Dryas cold spell. The end of the Younger Dryas has been dated to
about 9640 BC (11,590 calendar years BP).

In 2009 the
International Union of Geological Sciences (IUGS) confirmed a change in
time period for the Pleistocene, changing the start date from 1.8 to 2.588
million years BP, and accepted the base of the
Gelasian Stage
as the base of the Pleistocene.

The Pleistocene covers the recent period of repeated glaciations. The
name Plio-Pleistocene has in the past been used to mean the last ice age.
The revised definition of the
Quaternary, by pushing back the start date of the Pleistocene to 2.58
Ma, results in the inclusion within the Pleistocene of all the recent
repeated glaciations.

Paleogeography and Climate

The modern
continents were essentially at their present positions during the
Pleistocene, the
plates upon which they sit probably having moved no more than 100 km
relative to each other since the beginning of the period.

According
to one study, the Pleistocene's overall climate could
be characterized as a continuous
El Niño with
trade winds in the south
Pacific weakening or heading east, warm air rising near
Peru, warm
water spreading from the west Pacific and the
Indian Ocean to the east Pacific, and other El Niño markers.

Fauna

Both marine and continental faunas were essentially modern.

The severe climatic changes during the ice age had major impacts on the
fauna and

flora. With each advance of the ice, large areas of the continents
became totally depopulated, and plants and animals retreating southward in
front of the advancing glacier faced tremendous stress. The most severe
stress resulted from drastic climatic changes, reduced living space, and
curtailed food supply. A major extinction event of large
mammals (megafauna),
which included
mammoths,
mastodons,
saber-toothed cats,
glyptodons,
ground sloths,
Irish elk,
cave
bears, and
short-faced
bears, began late in the Pleistocene and continued into the Holocene.
Neanderthals also became extinct during this period. At the end of the
last ice age,
cold-blooded animals, smaller mammals like
wood
mice, migratory birds, and swifter animals like
whitetail deer had replaced the megafauna and migrated north.

The extinctions were especially severe in
North America where native
horses and
camels were
eliminated.

Humans During the Pleistocene

Scientific evidence
indicates that humans evolved (God completed their evolution, or finished
creating new species of humans) into their present form during the Pleistocene.
In the beginning of the Pleistocene Paranthropus species are still present, as well as early human
ancestors, but during the lower Palaeolithic they disappeared, and the only
hominid species found in fossilic records is Homo erectus for much of the Pleistocene. This species migrated
through much of the
old world, giving rise to many variations of humans. The Middle and late
Palaeolithic saw the appearance of new types of humans, as well as the
development of more elaborate tools than found in previous eras.

While the ultimate “African Origin” view of hominid evolution has not
been challenged, some researchers have posited that the last great expansion
did not eliminate pre-existing populations of hominids so much as assimilate
them upon contact with Homo sapiens. While this would suggest that
modifications in modern man may have been extensive and regionally based,
the theory remains controversial and has generally lost ground over the past
century, due to the advent of genetic evidence that directly contradicts it
in favor of a single-origin theory.

Deposits

Pleistocene non-marine
sediments are found primarily in fluvial
deposits, lakebeds, slope and
loess
deposits as well as in the large amounts of material moved about by
glaciers. Less common are
cave deposits,
travertines and volcanic deposits (lavas, ashes). Pleistocene marine
deposits are found primarily in shallow marine basins mostly (but with
important exceptions) in areas within a few tens of kilometers of the modern
shoreline. In a few geologically active areas such as the
Southern California coast, Pleistocene marine deposits may be found at
elevations of several hundred meters.